Performance Of Ion Doped In₂O₃ Enhanced NO₂ Gas Sensor

NO₂ gas is a kind of poisonous and irritating gas,the inhalation of NO₂ gas will damage the human respiratory tract.Therefore,semiconductor gas sensor technology is widely used in the field of real-time monitoring and detection of these gases.Indium oxide（In₂O₃）is a typical N-type wide-band gap metal oxide semiconductor,whose band width can range from 2.9 eV to 3.75eV depending on the morphology.The energy band structure is modified by energy band engineering so that it can be widely used in gas sensor,solar cell,photocatalysis and other fields.Nanostructured In₂O₃ is often used to measure NO₂ gas due to its high specific surface area,abundant defect structure and good electrical conductivity.Therefore,in this paper,the energy band structure and conductivity of the material are adjusted by doping,so as to improve the transport capacity of carriers and the adsorption capacity of NO₂ at room temperature,and finally achieve better sensitivity to NO₂ at room temperature.The main work is as follows:（1）Three kinds of In₂O₃ nanostructures were synthesized by different hydrothermal methods,and the morphologies were respectively In₂O₃ nanosheets,In₂O₃ nanocubes and In₂O₃ nanospheres.After that,its morphology and structure were characterized and its gas-sensitive properties were tested.Through the analysis of the test results of three kinds of materials,In₂O₃ nanospheres with more promising research prospects were selected for ion doping（2）Ag⁺doped In₂O₃ materials were synthesized by hydrothermal method.As a catalyst,metal dopants promote adsorption and surface reaction.Therefore,by increasing the response of the sensor,reducing the response and recovery time,reducing the operating temperature and increasing the selectivity,the sensor performance is enhanced and characterized by SEM,TEM,XRD,etc.,the sensor performance is also tested.By comparing the sensing properties,doped material samples with a certain proportion show better sensitivity and lower operating temperature.（3）A new type of S_x/In₂O_3-x material was synthesized by hydrothermal method.The anion exchange between sulfur and oxygen is used to regulate the energy band structure and conductivity of the material.The material is characterized by SEM,XRD,TEM,XPS and UV-vis absorption spectroscopy and the possible sensitive mechanism is explored.The transport capacity of the carrier and the adsorption capacity of NO₂ at room temperature were improved,and a good response to NO₂ was achieved at room temperature under UV-vis light.